Abstract:

Owing to low-energy hydraulic agents and fine-grained sediments, the fluvio-lacustrine basin proves to be ideal depositional system for preserving archaeological remains. The typical fluvio-lacustrine sediments in Nihewan Basin of North China are rich sources of Early to Middle Pleistocene archaeological sites, which offer an important opportunity to investigate human evolution and adaptive behaviors in East Asia. Comparing to the advances on the study of site formation processes of Lower Pleistocene sites have been handled in the basin, site formation focus on the Middle Pleistocene sites are yet to be carried out. In this paper, we present a site formation study of a newly discovered Middle Pleistocene archaeological site named Jijiazhuang site (JJZ) in Yuxian Basin (south part of Nihewan Basin). Two typical localities (JJZ-B and JJZ-E) are selected and geoarchaeological as well as archaeological factors are adopted for the site formation research. Through the analysis of geomorphology and deposits features, archaeological remains in JJZ-B were buried in marsh or swamp environment of lake margin deposits when the Nihewan old lake began retreating, while the archaeological sequence of JJZ-E probably belongs to the sand bar sedimentary face of lake margin environment. Multiple proxies from archaeological materials (artifacts spatial distribution, technological composition, weathering and abrasion condition, orientation as well as inclination) demonstrate that JJZ-B belongs to near primary context, the archaeological remains had been disturbed by low-energy sheet wash across the lake shore setting which provides effective information for exploring hominins technology and adaptive behaviors. Meanwhile, JJZ-E was preserved in secondary context where archaeological remains together with cobbles and pebbles were transported to accumulative area by relative high energetic hydraulic flow of lake wave and sheet wash, so that the locality witnessed low integrity of archaeological materials compared to JJZ-B. This study shows that the Nihewan Basin contains extensive information of archaeological remains of Middle Pleistocene. Formation processes of the different sites are strongly affected by the different settings in the archaeological landscape. Study on the site formation processes of JJZ site indicates that archaeological remains were in relative low density, and the formation processes varied from near primary context to secondary context. In addition, this study bears great significance on the study of the adaptive patterns of different localities of Jijiazhuang site complex by hominins during Middle Pleistocene.

Key words: Site formation processes, Lake shore environment, Middle Pleistocene, Jijiazhuang Paleolithic site, Yuxian Basin